The present invention relates generally to devices and methods for suturing body tissue. More particularly, the present invention is useful for performing end-to-side and end-to-end attachments of body ducts, such as in suturing coronary blood vessel grafts.
In many medical procedures today, it is desirable to connect a body duct, such as a hollow organ or blood vessel, to a targeted piece of tissue. In coronary surgery, this type of attachment is commonly referred to as an anastomosis. In coronary artery bypass graft surgery ("CABG"), a graft blood vessel may be anastomosized to an arterial wall of an artery to supply blood downstream of a blockage in another blood vessel. The proximal end of the blood vessel graft is typically connected to a pressurized arterial blood supply, such as the aorta, while the distal end is coupled to the vessel lumen downstream of the blockage. The amount of time spent performing these anastomosis procedures to connect blood vessel grafts between blocked arteries and pressurized blood supplies is critical to patient mortality and morbidity. In conventional CABG surgery, three critical determinates that affect the outcome of a bypass surgery are (1) time the patient spends on cardiopulmonary bypass, (2) time the patient spends with a clamped aorta, and (3) the quality of the anastomosis. It is generally understood that the risk of patient morbidity rises significantly after a threshold time of one hour on cardiopulmonary bypass. Continual circulation of blood through the mechanical apparatus of the bypass machine can cause various degradations to the blood. Perhaps the most prevalent complication arising from prolonged cardiac bypass is the high risk of distal thrombosis, which can embolize in the neurovasculature and potentially cause a stroke.
A critical factor in reducing the amount of time a patient spends on bypass is directly related to the time spent anastomosing the blood vessel grafts used during surgery. The average time for suturing one anastomosis is approximately seven to ten minutes. It is believed that an average CABG procedure involves approximately five anastomoses. Therefore, the average time for graft suturing ranges from thirty-five to fifty minutes, which is a significant portion of the sixty-minute threshold for patient morbidity. Patients treated with conventional coronary surgery and placed on cardiopulmonary bypass would benefit from reducing the amount of time spent performing each anastomosis.
In "off pump" procedures where patients are not placed on cardiopulmonary bypass and the heart remains beating, the difficulty of suturing an anastomosis graft on a moving surface of the heart may degrade the quality of such grafts completed on patients. "Off pump" procedures do not use cardiopulmonary bypass pumps or devices and thus reduces the blood damage associated with bypass devices. "Off pump" procedures, however, require a higher degree of expertise to perform coronary artery bypass grafts on a beating or moving object. An anastomosis differs from straight line suturing in that each suture has a different orientation that is based on its position around the cross-sectional circumference of the blood vessel graft. It can be appreciated that some of the sutures are easily made from on top of the conduit or blood vessel graft, while others are more difficult to complete as they are beneath the conduit. It can be further appreciated that performing such complex suturing procedures on a moving platform, such as the beating heart, further increases the difficulty associated with such suturing procedures. Improperly connecting blood vessel grafts to the patient may present substantial post-operative complications and/or increase operating room time spent correcting the improperly connected graft.
Accordingly, it would be desirable to provide improved devices and methods that simplify anastomosis graft procedures performed on patients, particularly where multiple graft procedures are to be performed. Simplifying the anastomosis procedure would typically reduce the time spent on each graft and thus minimize the time a patient spends on cardiopulmonary bypass. Additionally, it would desirable to provide a device that improves the consistency of the suture pattern created during each anastomosis graft.